The primary objective of the animal studies core is to provide standardized animal testing for quantitation of the immunogenicity of those vaccine candidates designed for mucosal priming which will produced by the individual projects of the program. All vaccine candidates will be tested in a standardized quantitative manner for immunogenicity after mucosal (intranasal) administration to mice, utilizing methodology developed and validated at the CVD 1. The results of this standardized testing will provide a means for ranking the relative immunogenicity of the more than 80 vaccine candidate constructs. This ranking will be used to select the most immunogenic candidates for studies of priming and boosting strategies, and to test for vaccine efficacy in animals. The secondary objective of the animal studies core is to provide specialized services to meet the additional needs of individual projects for parenteral immunizations, assessment of protective efficacy, and vaccine safety protocols, a) A limited number of parenteral immunization studies of mice will be performed using purified proteins to test the immunogenicity of the domains of anthrax LA prior to expressing them as fusion proteins with PA (protective antigen). The immunogenicity of the LA/PA fusion proteins will also be tested in this manner (Project 1). b) The animal studies core will perform a limited number of studies of the protective efficacy of monovalent Salmonella-based (Project 4) and Vibrio cholerae -based (Project 2) vaccines against the individual serotypes of Botulinum toxin, c) The animal core will formally evaluate the safety of newly developed, live, attenuated strains of Yersinia in mice using standardized assays for mouse lethal dose 50% (MLD50)Of the strains (Project 3). d) Since most prior animal studies on the mucosal immunogenicity, and protective efficacy, of attenuated Vibrio cholerae strains have been obtained using oral inoculation of rabbits, Vibrio cholerae-based vaccines will also be tested by this method (Project 4).